Search

The NASA receiver is specifically designed for use in coherent LiDAR systems that leverage high-energy (i.e., > 1mJ) fiber laser transmitters. Within the receiver, an outgoing laser pulse from the high-energy laser transmitter is precisely manipulated using robust dielectric and coated optics including mirrors, waveplates, a beamsplitter, and a beam expander. These components appropriately condition and direct the high-energy light out of the instrument to the atmosphere for measurement. Lower energy atmospheric backscatter that returns to the system is captured, manipulated, and directed using several of the previously noted high-energy compatible bulk optics. The beam splitter redirects the return signal to mirrors and a waveplate ahead of a mode-matching component that couples the signal to a fiber optic cable that is routed to a 50/50 coupler photodetector. The receiver’s hybrid optic design capitalizes on the advantages of both high-energy bulk optics and fiber optics, resulting in order-of-magnitude enhancement in performance, enhanced functionality, and increased flexibility that make it ideal for long-distance or low-backscatter LiDAR applications. The related patent is now available to license. Please note that NASA does not manufacturer products itself for commercial sale.

The novel Vision-based Approach and Landing System (VALS) provides Advanced Air Mobility (AAM) aircraft with an Alternative Position, Navigation, and Timing (APNT) solution for approach and landing without relying on GPS. VALS operates on multiple images obtained by the aircraft’s video camera as the aircraft performs its descent. In this system, a feature detection technique such as Hough circles and Harris corner detection is used to detect which portions of the image may have landmark features. These image areas are compared with a stored list of known landmarks to determine which features correspond to the known landmarks. The world coordinates of the best matched image landmarks are inputted into a Coplanar Pose from Orthography and Scaling with Iterations (COPOSIT) module to estimate the camera position relative to the landmark points, which yields an estimate of the position and orientation of the aircraft. The estimated aircraft position and orientation are fed into an extended Kalman filter to further refine the estimation of aircraft position, velocity, and orientation. Thus, the aircraft’s position, velocity, and orientation are determined without the use of GPS data or signals. Future work includes feeding the vision-based navigation data into the aircraft’s flight control system to facilitate aircraft landing.

The novel approach for optimizing airspeed for both actual and predicted wind conditions in electric Vertical Takeoff and Landing (eVTOL) aircraft with Distributed Electric Propulsion (DEP) systems includes the process of creating a lookup table for wind‐optimal airspeed as a function of wind magnitude, considering the direction of the wind relative to the cruise segment, considering the cruise altitude for an aircraft type, and incorporating the wind-optimal airspeed lookup table in the performance database for real‐time access by the Flight Management Systems (FMS) to predict wind-optimal airspeed at waypoints of the flight plan. The target wind‐optimal airspeed is updated in real-time throughout the cruise portion of a flight. In a test of the wind-optimal airspeed targeting technique using a multi-rotor aircraft model, results obtained show benefits of flying at the wind‐optimal cruise airspeed compared to the best‐range airspeed. In headwind conditions, energy consumption was reduced by up to 7.5%, and flight duration was reduced by up to 28%. Under uncertain wind magnitudes, flying at wind-optimal airspeed offered lower variability and higher predictability in energy consumption than flying at best‐range airspeed.